煤矸石堆积区周边土壤重金属污染特征与植物毒性

Pollution Characteristics and Phytotoxicity of Heavy Metals in the Soil Around Coal Gangue Accumulation Area

煤矸石在自然堆积过程中会通过风化和雨淋条件释放重金属等污染物质,从而对周边土壤环境造成严重的生态危害.研究了矸石山周边土壤中重金属含量,探讨了土壤样本暴露诱导的植物毒性效应,以期全面评估矸石堆积区周边土壤的生态风险.结果表明,煤矸石堆积区周边土壤中Cd、Pb和Zn的含量平均值均超过山西省土壤元素背景值,并且随着距矸石山的距离越远,土壤重金属含量呈现先上升后下降的趋势;富集因子结果同样显示周边土壤中Cd、Pb和Zn元素污染较严重.暴露于距矸石山不同距离的土壤后,大麦幼苗生长受抑,部分土壤诱导叶绿素含量降低和丙二醛(MDA)含量升高,超氧化物歧化酶(SOD)、过氧化物酶(POD)和谷胱甘肽(GSH)活性上升,过氧化氢酶(CAT)活性显著下降,并且造成根尖细胞中有丝分裂指数(MI)降低和微核率(MN)显著上升.皮尔森相关系数表明,矸石堆积区周边土壤中Cr、As和Zn元素分别与大麦芽重、根重和微核率之间呈显著的正相关,Cu和Pb元素分别与叶绿素和微核率之间呈显著的负相关.

Coal gangue releases heavy metals and other pollutants through weathering and rain conditions during the natural accumulation process,which causes serious ecological risks to the surrounding soil environment.This study aimed to analyze the content of heavy metals in the soil around a coal gangue dump and to explore the phytotoxic effects induced by the exposure of soil samples to comprehensively assess the ecological risks of the soil around the coal gangue accumulation area.The results showed that the average contents of Cd,Pb,and Zn in the soil around the coal gangue accumulation area exceeded the background values of soil elements in Shanxi Province,and the content of heavy metals in the soil first increased and then decreased with the distance from the coal gangue dump.The enrichment factor results also showed that the pollution of Cd,Pb,and Zn in the soil was serious.The growth of barley seedlings was inhibited after exposure to the soil at different distances from the gangue dump,and some soils could induce the decrease in chlorophyll and the increase in MDA content;the increase in SOD,POD,and GSH activities;the significant decrease in CAT activities;and the decrease in mitotic index(MI)and significant increase in micronucleus rate(MN)in root tip cells.The Pearson correlation coefficient showed that Cr,As,and Zn were significantly positively correlated with the shoot weight,root weight,and micronucleus rate of barley,whereas Cu and Pb were significantly negatively correlated with the chlorophyll and micronucleus rate,respectively.